1. Field of the Invention
The present invention relates to a plant disease resistance-inducing gene from the soil metagenome and a use thereof. More specifically, it relates to a recombinant vector containing a plant disease resistance-inducing 1B8-4-D7 gene from the soil metagenome, a host cell transformed with the recombinant vector, a recombinant protein produced by the transformed host cell, a plant disease resistance enhancer including the transformed host cell or the recombinant protein as an effective component, a method of enhancing resistance against plant pathogens having elicited induced resistance by treating a plant with a composition including the transformed host cell or the recombinant protein, and a preparation for controlling plant disease having the transformed host cell or the recombinant protein.
2. Description of the Related Art
There is a difference between the numbers of various microorganisms observed from the natural environment and the numbers of colonies shown in a culture plate, and the difference can be defined as the ‘plate-count anomaly.’ (Amann et al. (1995) Microbiol. Rev. 59: 143-169). In the late 1970s, there was a suggestion that the DNA of microorganisms should be directly isolated from their natural habitat and the constitutive genes of their genome should be studied as they are (Torsvik V. L. and Goks J. (1978) Soil Biology & Biochemistry 10: 7-12), which later led to the new ‘metagenome’ terminology. Metagenome was defined as a “group of genome of all microorganisms that are present in a certain given environment” (Handelsman et al. (1998) Chem. Biol. 5: R245-249), and the study of the direct cloning of metagenomic DNA was first led by Pace and DeLong in the U.S. (Schmidt et al. (1991) J. Bacteria 173: 4371-4378).
Performing a study of microorganisms after completely identifying and classifying them via culture is one particular way to study the microorganisms. However, this method is difficult to realize in the real world. For example, although SAR11 bacteria are a dominant species in various sea environments all over the world, only recently has it been successfully cultured, but the culture thereof was not based on conventional pure culture methods, which involve growing a colony on a solid medium (Morris et al. (2002) Nature 420: 806-810). Further, with the simulation of a natural environment for culture growth using the diffusion chamber method, it became possible to obtain colonies of microorganisms which could not be cultured before because it was found that some microorganisms do not grow on artificial media, but can grow via natural interactions with other microorganisms.
The biggest advantages for studying microorganisms and their diversity via studying the metagenome are that, first, a gene can be studied without culture, and second, a comprehensive understanding can be made regarding the surrounding environment.
An enzyme is a complex protein catalyst produced by a living organism, and an enzyme can also referred to as a biocatalyst. The reason why the metagenome has received attention in recent years is that it can be useful, as its application area, for the search of new substances or enzymes. Examples of enzymes that are widely used in industrial processes include chitinase, lipase/esterase, protease, amylase, DNAse, and xylanase, which mainly hydrolyze polymeric material. Other enzymes include polyketide synthase, 4-hydroxybutyrate DH, and oxygenase (Lorenz et al. (2002) Curr Opin Biotechnol 13: 572-577). However, the recent tendency is, apart from the enzymes being used for hydrolyzing a polymer, to utilize enzymes originating from microorganisms or the metagenome as a catalyst in a reaction required for a chemical synthetic process.
A group of genes from the soil metagenome, which encode antibiotic resistance, have been disclosed in Korean Patent Registration No. 0952754, and a novel lipase gene from the soil metagenome and a lipase protein encoded by the lipase gene have been disclosed in Korean Patent Registration No. 0613694. However, there is absolutely no disclosure suggesting that a novel gene isolated from the soil metagenome can be used for enhancing the disease resistance of a plant as described in the present invention.